import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class TcpEchoServer {

    private ServerSocket serverSocket ;

    public TcpEchoServer(int port) throws IOException {
        this.serverSocket = new ServerSocket(port);
    }
    public void start() throws IOException {
        System.out.println("服务器启动");
        ExecutorService service = Executors.newCachedThreadPool();
        while (true){
            Socket clientSocket = serverSocket.accept();
            service.submit(()->{
                try {
                    precessConnection(clientSocket);
                } catch (IOException e) {
                   e.printStackTrace();
                }
            });
        }
         
    }

    private void precessConnection(Socket clientSocket) throws IOException {
        System.out.printf("客户端[%s,%d]上线\n" , clientSocket.getInetAddress().toString() , clientSocket.getPort());
        try(InputStream inputStream = clientSocket.getInputStream();
            OutputStream outputStream = clientSocket.getOutputStream();){
            Scanner scan = new Scanner(inputStream) ;
            while (true){
                if(!scan.hasNext()){
                    System.out.printf("客户端[%s,%d]下线\n" , clientSocket.getInetAddress().toString() , clientSocket.getPort());
                    break;
                }
                String request = scan.next() ;
                String response = process(request);
                PrintWriter writer = new PrintWriter(outputStream) ;
                writer.println(response);
                writer.flush();
                System.out.printf("[%s,%d]request=%s , response=%s\n" ,clientSocket.getInetAddress().toString() , clientSocket.getPort() ,request , response);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }finally{
            clientSocket.close();
        }

    }

    private String process(String request) {
        return request ;
    }

    public static void main(String[] args) throws IOException {
        TcpEchoServer server = new TcpEchoServer(9090) ;
        server.start();
    }
}
